Conventional internal combustion engines utilize approximately 30% of the total energy available from any given amount of fuel. The remaining unused energy is consumed by chemical reactions, frictional losses, and engine exhaust. Such a low fuel economy may be improved by recovering at least a portion of the unused energy.
One attempt to improve fuel economy by recovering at least a portion of the unused energy can be found in U.S. Pat. No. 5,176,000 (the '000 patent) issued to Dauksis on Jan. 5, 1993. The '000 patent discloses a system for recovering energy lost to engine exhaust. The system includes a cooling system in fluid communication with a plurality of engine cylinders, an engine exhaust manifold, and a turbine. A fluid in a liquid state initially absorbs heat from the combustion process occurring in the engine cylinders raising the temperature of the fluid and maintaining the temperature of the engine within a desired range. After absorbing heat from the engine cylinders, the fluid flows around the engine exhaust manifold. There, the fluid absorbs heat from the exhaust gas further raising the temperature of the fluid. Upon absorbing heat from the engine exhaust manifold, the fluid temperature becomes high enough to turn the fluid into a gas. The gas is then directed to and drives a turbine, which is connected to a generator. As the turbine rotates, it drives the generator producing electric power. The generated electric power may be stored or used to power an electric motor.
Although the system in the '000 patent may improve fuel economy by recovering the portion of energy lost to engine exhaust, the fuel economy improvement may be limited. In particular, the '000 system focuses only on recovering energy lost to engine exhaust and ignores other potential sources of unused energy. For example, some of the available energy is lost through chemical reactions such as those found in catalytic exhaust treatment devices. By focusing only on one potential source of unused energy, fuel economy improvement may be limited and potential operational cost savings may not be fully realized.
The disclosed system is directed to overcoming one or more of the problems set forth above.